Hi, I'm running a chevy 53 235ci with a th350 auto. The tranny was just rebuilt by the local trannyguy (been doing auto trannys for 30+ years). Now to the problem, it wont shift into 3rd gear. I have 1st, 2nd and R... Checked the guvernor, seems Ok. KD kable not connected. Could this be a vaccum problem? Should I try with extra vaccum (I have a gaspump with extra vaccum that supposed to go to the wipers). Anybody running this combo? Thanks Peter
Try the very best vacuum source you have on the intake, if the kickdown is disconnected and the cable isn't binding, and the governor is in good shape then it could possibly be weak vacuum, though that should affect the 1-2 shift just as much as the two three shift. Having a solid reverse indicates the third gear clutch pack is holding. Even experienced builders can make a mistake, if all of the obvious items check out it is probably internal.
Ok thanks. Yes, since 1 - 2 is working it's probably something else than vacuum issues. I will still cross my fingers and try the extra vacuum.... If that doesnt work I'll return it. I had a power glide, changed to open drivline, still have a power glide=Sucks
The "KD Kable" is really a TV cable standing for Transmission Valve. I hoestly don't know if that would effect 3rd gear shift but I do know not having the cable hooked up and adjusted properly will probably void any warranty the rebuilder has or implies. Simple answer is you need to hook up and adjust the cable properly for the tranny to wor right
Sorry, I had trouble getting away from TeleVision, wrong name but I stick by the advise, by the way thank-you for the correction.
In a TH 350 if the Kick Down cable is not hooked up it should still shift, Unless the cable is binding or stuck inside the trans, holding it in the WOT position. The transmission would then think it is asking for full throttle kick down shift. Even then it should still shift but would be at a high rpm/mph. TV cable as some would call it is referred to on a 700r4/4l60. It is very critical these are adjusted properly. It controls fluid pressure depending on throttle position. If not connected and adjusted on 700r4/4l60 it is certain death.
You say you have a 350 ,you must have changed it.The powerglide orginal reverse is all the way down, like 1st in manual. I go with outlawracer kick down is stuck in wrong postion.
Tried the extra vacuum...still no 3rd gear. With the extra vacuum I have almost 20" on my vacuum meter. That should be more than enough for an idling engine...right? I think I read somewhere that around 16 should be enough. As I understand it, the th350 should still shift even if the KD cable is not connected. I just have a small plugged hose where the KD wire should go down, so there is no binding. Also when I removed the oilpan I looked at the KD, and it was ok. I think i'll tear it down and return it. Thanks for all the input.
Yeah... I've had to take the same transmission back to a reputable shop more than once.. they do miss things and make mistakes.. doesn't mean the shop is bad.. just means people make mistakes from time to time or get in a hurry? Definitely take it back.. they'll make it right.
Could it be that it is only in second and not Drive on the gear selector? My limited skills dictate that I check the real simple stuff before I tear things apart.
The TH350 does not use a manual throttle valve, the throttle valve is controlled via the vacuum modulator. The linkage or cable going to the transmission is for kickdown only. If the kickdown lever is not connected, it might be possible that the kickdown lever is in the kickdown position and therefore all shifts would be at the highest speed the governor and vacuum modulator allow the shifts to be at. What speed does it shift out of 1st with partial throttle? If it is higher than 20-30mph, then the kickdown lever might be sitting in the kickdown position. If this is the case, your 2nd-3rd shift would be up near 60-70mph all the time.
It has no effect with the trans going into third gear. But it may affect "When" it goes into third gear. I'm leaning towards a vacuum problem or modulator issue.
Just found out today my TH 350 isn't going into third either. There is no cable attached to the trans; I'm guessing it was removed at some time in the past. Where does it connect inside? Guess I gotta drop the pan to check this out so any info would be helpful. I'm a 4 speed guy and haven't worked on an auto trans for many years, need all the advice I can get.
Ive had a similar problem with a couple Th-350's, one was low vacuum, one was no vacuum (forgot to hook the hose to the modulator). It might be that you have a bad vacuum modulator.
I had a similar problem on a TH350 I rebuilt myself. The seal ring on the rear drum was wedged when I put the drum in the case during assembly and I didn´t notice it. The tranny had no 3rd gear. I went through it once more and saw the damage . TH350s are quite obvious if you´re looking for a problem, it usually can be determined easily. But my gut says you gotta pull the tranny and take it back to the tranny man.
It goes into 2nd gear almost right after take off, so I don't think it's a kickdown problem. I also suspected the modulator, so a bought a new adjustable one. Tried with the screw all the way out. Still no 3rd gear.
It´s no biggie, the rear drum seal just can´t hold the oil pressure and therefore there´s no 3rd. To be honest, I tried to kick my ass for screwing up but stuff like that happens.